Selective removal of dissolved organic matter affects the production and speciation of disinfection byproducts.

The heterogeneity of dissolved organic matter (DOM) in natural and human impacted waters and the variety of drinking water treatment processes employed has made a mechanistic understanding of disinfection byproduct (DBP) formation challenging. In this study, we examined the formation of the regulated DBPs (Trichloromethanes, THM, and Haloacetic acids, HAA) during full-scale water treatment operations both with prechlorination treatment (normal operations for the drinking water plant) and without (altered operations); followed by coagulation, flocculation, filtration, and chlorination. The source water DOM concentration ranged 6.4 to 7.3 mg-C/L. DOM composition was moderately humic and degraded with a mix of microbial- and terrestrial-like characteristics. Removal of raw water prechlorination caused an average reduction in total THM and HAA concentrations of 52.7% and 40.0%, respectively, with the greater reduction noted for chlorinated-DBPs rather than brominated-DBPs. Prechlorination treatment resulted in a higher relative production of Cl3CH and BrCl2CH associated with aromatic, humic, and terrestrial-like DOM. Without prechlorination, the DBP pool had higher proportions of brominated-DBPs (Br3CH, Br2ClCH, Br2CHCOOH, BrClCHCOOH, and BrCH2COOH) associated with microbial-like, processed humic-like, and protein-like DOM. These observed patterns could not be explained by chloride demand and DOM concentration, indicating that DOM composition played an important role in DBP formation.

PM10 air pollution exposure during pregnancy and term low birth weight in Allegheny County, PA, 1994-2000.

PURPOSE: Low birth weight has been associated with increased risks of mortality and/or morbidity in childhood and adulthood. Epidemiological studies suggest that maternal exposure to air pollution, especially particulate matter during pregnancy, is associated with an increased risk of delivering a low birth weight infant. The aim of this study is to explore the association between exposure to particulate matter (PM10) during pregnancy and term low birth weight (LBW: birth weight <2,500 g and gestation age ≥ 37 weeks). METHODS: Birth data from the Allegheny County Health Department, Pittsburgh, PA, USA and PM10 air data generated with inverse-distance interpolation by RAND's Center for Population Health and Health Disparities, were obtained. The study population consisted of all term singleton live births (gestational age ≥ 37 weeks) born between January 1, 1994 to December 31, 2000. Infants with birth weight <2,500 g were classified as LBW. Logistic regression with robust variance estimation was performed to estimate the odds ratios of LBW per inter-quartile range increase in PM10. RESULTS: The results showed that the odds ratios of term LBW per inter-quartile range increase in PM10 were 1.13 (95% CI: 1.02-1.25) during the first trimester and 1.10 (95% CI: 1.00-1.22) during the second trimester after adjustment for other important covariates, respectively. CONCLUSION: The findings of the study support the hypothesis that exposure to PM10 is associated with increased levels of term LBW. Further studies are warranted to corroborate these findings.